Report 2022-106 Recommendation 2 Responses

Report 2022-106: Department of Water Resources: Its Forecasts Do Not Adequately Account for Climate Change and Its Reasons for Some Reservoir Releases Are Unclear (Release Date: May 2023)

Recommendation #2 To: Water Resources, Department of

To ensure that its water supply forecasts better account for the observed effects of climate change as soon as possible, DWR should continue to implement its plan to adopt an updated water supply forecasting model and updated procedures. By November 2023 DWR should also do the following:

1. Publish on its website a timeline affirming when it will implement its updated model and procedures across all of the watersheds for which it produces a water supply forecast.

2. Establish and publish the specific criteria that it will employ to determine when its updated model has demonstrated sufficient predictive capability to be ready for use in each of the watersheds.

3. Provide annual updates on its website regarding the status of its implementation of the updated model and procedures.

1-Year Agency Response

Department of Water Resources (DWR) will post annual updates to the Roadmap to Climate Resilient Forecasting on the public-facing website: https://snow.water.ca.gov. DWR is also developing a work plan to provide additional details on the process and requirements to assess and document forecast improvement with the new forecasting tools. Specifically, DWR is developing and implementing updated models in line with the work plan. DWR also continues to work with partner agencies and the academic community to gain experience with the new tools for forecasting. This will enable the team to develop criteria to assess forecast improvement. The work plan will be posted on the website noted above and will be updated annually or as progress is achieved. The budget crisis of 2024 has led to a prioritization of fiscal resources, which may delay implementation of components of the Roadmap to Climate Resilient Forecasting and work plan.

California State Auditor's Assessment of 1-Year Status: Partially Implemented

DWR has created a roadmap, available on its website, that will be updated annually. This roadmap provides a timeline of DWR's adoption of new forecasting models and procedures. The specific criteria for assessing forecast improvement have not been developed yet as DWR is still developing and implementing updated models. We look forward to assessing DWR's efforts to implement this recommendation as part of our regular follow-up process.

6-Month Agency Response

In March 2023, DWR adopted the Roadmap for a Climate Resilient Forecasting Framework (Roadmap) that includes annual forecast modeling assessments, latest developments, and achievements. The Roadmap is publicly available on DWR's website (Link: https://water.ca.gov/roadmap) and is a working document and will continually be updated.

Criteria to assess model accuracy are published on dashboards and written reports will be updated annually. This information will be publicly accessible on DWR's new California Cooperative Snow Surveys Program website (https://snow.water.ca.gov) in November 2023.

DWR publishes a Hydroclimate Report and presentations on annual forecasting assessment that includes observed effects of climate change on the Department's California Data Exchange Center's website. The next Hydroclimate Report will be available in April 2024 for the previous water year.

California State Auditor's Assessment of 6-Month Status: Pending

DWR's roadmap does not include some additional information that it should. For example, DWR has not yet provided specific information regarding when it will implement its new forecasting models across all watersheds, or shared criteria for how it will determine whether the model is ready for use in a watershed. We look forward to reviewing that information when DWR provides it.

60-Day Agency Response

In March 2023, DWR adopted the Roadmap for a Climate Resilient Forecasting Framework (Roadmap) that includes annual forecast modeling assessments, latest developments, and achievements. The Roadmap is publicly available on DWR website (Link: https://water.ca.gov/roadmap) and is a working document and will continually be updated.

DWR publishes a Hydroclimate Report and presentations on annual forecasting assessment that includes observed effects of climate change on the Department's California Data Exchange Center's website. The next Hydroclimate Report will be available in April 2024 for the previous water year.

California State Auditor's Assessment of 60-Day Status: Pending

DWR posted the Roadmap on its website, however, as we discuss in the text of the report, the Roadmap does not yet include accountability mechanisms to ensure that it implements its new model promptly. Further, although the plan includes the objective of developing forecast model performance tools, it does not contain specific criteria for determining whether the new model is sufficiently accurate for use or a timeline for implementation. We look forward to following DWR's progress in implementing its planned updates to its forecasting methodology in future updates.

All Recommendations in 2022-106

Agency responses received are posted verbatim.